Created originally for military purposes, the Alhambra in Granada, Andalusia, Spain, was a fortress, a palace and a small medina all at once. This helps us to understand the characteristics of this monument.

The word Alhambra (Spanish), is derived from an Arabic word meaning "red castle or vermilion", perhaps due to the color of the towers and walls that completely surround the hill of La Sabica, which appear silver under the starlight, but in the sunlight it acquires a golden tone. There is a more poetic explanation for it, narrated by the Muslim chroniclers; "under the light of torches."

There is no reference to the Alhambra as a royal palace until the 13th century, although fortification has existed since the 9th century. The monarchs Ziries were in all probability the emirs who built the Alhambra, beginning in 1238.

The founder of the ruling Nasrid dynasty, Muhammed I Al-Ahmar (1195 –1273), began with the restoration of the old fort. This was completed by his son Muhammed II, whose successors continued the repairs. The construction of the palaces (Casa Real Vieja) dates back to the 14th century and is the work of two great kings: Yusuf I and Muhammed V. The first is awarded the Fourth Comares, the Door of Justice , the Baths and towers. Muhammed V, completed the beautification process and the Hall of Lions, in addition to other rooms and fortifications (1302 - 1492).

The Alhambra became a Christian court in 1492 when the Catholic monarchs conquered Granada.

More Info: en.m.wikipedia.org